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Species-level identification of insects is often difficult and can limit ecological studies, particularly those assessing insect biodiversity. Wing venation characteristics are fundamental for defining and classifying insects. Bees (Hymenoptera: Apoidea) have relatively conserved wing characteristics at the family, genus, and species level, but the patterns between groups remain poorly understood. In this study, we employed geometric morphometrics to assess variation in wing venation across bees taxa. Geometric morphometrics allows for detailed shape analysis of wing structure, which may provide insights into evolutionary relationships. By digitally landmarking nine homologous wing vein characters of a diverse sample of bees, we quantified and compared phenotypic variation across several recognized species, genera, and families in order to assess whether the resulting morphological clusters reflect evolutionary divergence. Preliminary results demonstrate the ability to differentiate species within a genus and even among populations, testifying to a high level of precision. We are currently investigating the extent to which our groupings based on morphometric data aligns with established phylogeny and the practical implications. This study assesses the potential of geometric morphometrics to infer the phylogenetic placement of indeterminate bee species based solely on wing vein patterns and provides an effective pathway for species identification. This classification method could accelerate research in pollinator conservation and ecology by offering an accessible alternative means for bee identification and ecological morphotype hypotheses.This poster was presented at the UCSB Undergraduate Research Colloqium- 2024

Wing venation characteristics are fundamental for defining and classifying insects. In bees these characteristics are relatively conserved, but the patterns between groups remain poorly understood. We employed geometric morphometrics to assess variation in wing venation across bees taxa. Geometric morphometrics allows for detailed shape analysis of wing structure, which may provide insights into evolutionary relationships. By digitally landmarking homologous wing vein characters of a diverse sample of bees, we quantified and compared phenotypic variation in order to assess whether the resulting morphological clusters reflect evolutionary divergence and align with established phylogeny. This study assesses the potential of geometric morphometrics to infer the phylogenetic placement of indeterminate bee species based solely on wing vein patterns and provides an effective pathway for species identification.Presented at the UCSB EEMB Undergraduate Research Symposium 2024

Honey bee, Apis mellifera L. (Hymenoptera: Apidae), colonies and individuals respond variably to disturbances. The response depends on perception and interpretation of stimuli requiring both neural modulation and use of energy. In this study, we examined the role of neural modulation and brain metabolism in constitutive and experience‐dependent differences in defensive response. For constitutive differences, we compared brain gene expression in bees from gentle and defensive colonies identified in a standard colony‐level assay. For experience‐dependent changes in defensiveness response, we compared brain gene expression in control bees and bees that responded by sting extension to electric shock in a standardized individual behavioral assay. In both experiments, for neuromodulation, we examined membrane receptor genes for the biogenic amines dopamine (DopR2), octopamine (OA1), and serotonin (5HT2a), as well the gene for the enzyme responsible for serotonin synthesis (THR). For neural metabolism, we examined the expression of two Oxidative Phosphorylation Pathway “OXPHOS” genes (ND51 and ND20‐LIKE). Bees collected from defensive colonies had a significantly lower expression of amine receptor, synthesis gene, and OXPHOS genes. However, bees responding to noxious stimuli (i.e., electric shock) showed greater gene expression for both OXPHOS and neuromodulation genes, except for 5HT2a. We discuss the intriguing intersection of neuromodulation and neural metabolism in defensive response both for constitutive differences, and contrasting experience dependent or adaptive differences. [ABSTRACT FROM AUTHOR]

Nosemosis is one of the most devastating diseases of Apis mellifera (Honey bees) caused by the single-celled spore-forming fungi Nosema apis, N. ceranae and N. neumanii, causing a severe loss on the colony vitality and productivity. Fumagillin, a MetAP2 inhibitor, was a certified treatment for controlling nosemosis, nevertheless, due to its deleterious effects on honey bees and humans, it is prohibited. So, searching for novel biological agents with affordable selectivity to target Nosema species infecting Apis mellifera, with nil toxicity to bees and humans is the main objective of this study. Nosema species were isolated from naturally infected honey bees. The methanolic extracts of Acacia nilotica, Elaeis guineensis, and Catharanthus roseus were tested to selectively control the growth of Nosema spp of honeybees. The spores of Nosema species were molecularly and morphologically identified. Among the tested plant extracts, the methanolic extracts (0.1%) of A. nilotica had the most activity towards Nosema spp causing about 37.8 and 32.5% reduction in the spores' load at 5- and 9-days post-infection, respectively, compared to the untreated control. At 0.1%, the A. nilotica methanolic extract exhibited the highest inhibitory effect for Nosema spores, without any obvious bee mortality. Catharanthus roseus displayed a reduction of spores by 27.02%, with bee mortality rate of 27.02%. At 1% for 5 dpi, the A. nilotica extracts led to 18.18% bee mortality, while the C. roseus extracts resulted in 100% mortality, as revealed from the toxicity and quantification bioassays. So, the extracts of A. nilotica and C. roseus had a significant effect in controlling the N. apis and N. ceranae titer compared to the infected untreated control at both time points. The titer of N. apis and N. ceranae was noticeably decreased by more than 80% and 90%, in response to A. nilotica, compared to the control. From the metabolic profiling by GC–MS analysis, the most frequent active compounds of A. nilotica were 2,4,6-trihy-droxybenzoic acid, 1,2-dihydroxybenzene, myristic acid, and linoleic acid. These compounds were analyzed in silico to assess their binding affinity to the ATP binding protein, methionine aminopeptidase and polar tube protein of Nosema species as target enzymes. The compound 2,4,6-trihydroxybenzoic acid had the lowest energy to bind with ATP binding protein, methionine aminopeptidase and polar tube protein of Nosema, followed by 1,2-dihydroxybenzene and myristic acid, compared to fumagilin. So, from the experimental and molecular docking analysis, the extracts of A. nilotica had the highest activity to attack the cellular growth machinery of Nosema species without an obvious effect to the honeybees, ensuring their prospective promising application. [ABSTRACT FROM AUTHOR]

Polyunsaturated fatty acids (PUFAs) are dietary components participating in neurotransmission and cell signaling. Pollen is a source of PUFAs for honeybees, and disruptions in dietary PUFAs reduce the cognitive performance of honeybees. We reveal that gut bacteria of honeybees contribute to fatty acid metabolism, impacting reward learning. Gut bacteria possess Δ-6 desaturases that mediate fatty acid elongation and compensate for the absence of honeybee factors required for fatty acid metabolism. Colonization with Gilliamella apicola , but not a mutant lacking the Δ-6 desaturase FADS2, increases the production of anandamide (AEA), a ligand of the endocannabinoid system, and alters learning and memory. AEA activates the Hymenoptera-specific transient receptor AmHsTRPA in astrocytes, which induces Ca2+ influx and regulates glutamate re-uptake of glial cells to enhance reward learning. These findings illuminate the roles of gut symbionts in host fatty acid metabolism and the impacts of endocannabinoid signaling on the reward system of social insects. [Display omitted] • Gut microbiota mediate the effects of PUFAs on honeybee reward learning and memory • Gilliamella apicola harboring FADS2 aids in converting LA to anandamide • Anandamide activates the AmHsTRPA channel in astrocytes, triggering Ca2+ influx • AmHsTRPA regulates the glutamate/GABA balance in astrocytes, promoting reward learning Zhong et al. reveal that honeybee gut microbiota influence reward learning by mediating the metabolism of pollen PUFAs. Gilliamella apicola harboring FADS2 facilitates the conversion of linoleic acid (LA) to anandamide, which activates AmHsTRPA in astrocytes. This activation triggers Ca2+ influx and regulates glutamate/GABA balance in glial cells, ultimately enhancing honeybee reward learning. [ABSTRACT FROM AUTHOR]

The miRNA plays a key role in the regulation of hormone signaling in insects. The pathways by which miRNAs affect hormone levels are unclear in the honeybee (Apis mellifera), an indispensable pollinator in nature. In this study, ame-miR-5119 was overexpressed and knocked down in larvae by feeding mimics and inhibitors, respectively, and we determined that ame-miR-5119 regulates hormone signaling through the target gene ecdysis triggering hormone (Eth), which affects the larval-pupal transition of workers. The results showed that ame-miR-5119 with a length of 19 nt targets six genes related to the hormone pathway. We focused on Eth and found that ame-miR-5119 and Eth exhibited reverse expression patterns during the transition from larval to pupal stages in workers. Dual luciferase assay confirmed the negative regulatory between ame-miR-5119 and Eth. Overexpression of ame-miR-5119 decreased the mRNA level of Eth , and the Eth receptor (Ethr) expression was not significantly affected, but the expression levels of juvenile hormone (JH) pathway related genes juvenile hormone acid methyltransferase (Jhamt) and Krüppel homolog 1 (Kr-h 1) were significantly reduced. In contrast, knockdown of ame-miR-5119 increased the mRNA level of Eth , and the expression of Ethr , Jhamt and Kr-h 1 was significantly upregulated. ame-miR-5119 did not affect larval body weight. The number of larvae overexpressing ame-miR-5119 survived in the prepupal stage was lower than that in the control group, and the number of pupations reduced at 11-day-old. The number of larvae that knocked down ame-miR-5119 survived in the prepupal stage was significantly higher than that in the control group, and the number of pupations increased at 11-day-old. These results indicated that ame-miR-5119 negatively regulates the expression of Eth , indirectly inhibits the expression of Ethr , Jhamt , and Kr - h 1, and affects the JH biosynthesis, thereby preventing the metamorphic transition from larva to pupa in worker bees. These findings provide evidence that the miRNA regulation of hormone levels in honey bees. [ABSTRACT FROM AUTHOR]

As pollinators, bees are key to maintaining the biodiversity of angiosperm plants, and for agriculture they provide a billion-dollar ecosystem service. But they also compete for resources (primarily nectar and pollen), especially the highly social bees that live in perennial colonies. So, how do they organize their daily temporal activities? Here, we present a versatile, low-cost device for the continuous, automatic recording and data analysis of the locomotor activity in the colony-entrance tube of highly eusocial bees. Consisting of an in-house built block containing an infrared detector, the passage of bees in the colony entrance tunnel is registered and automatically recorded in an Arduino environment, together with concomitant recordings of temperature and relative humidity. With a focus on the highly diverse Neotropical stingless bees (Meliponini), we obtained 10-day consecutive recordings for two colonies each of the species Melipona quadrifasciata and Frieseomelitta varia, and also for the honey bee. The Lomb-Scargle periodogram analysis identified a predominant circadian rhythmicity for all three species, but also indications of ultradian rhythms. For M. quadrifasciata, which is comparable in size to the honey bee, we found evidence for a possibly anticipatory activity already before sunrise. As all three species also presented activity at night in the colony entrance tube, this also raises questions about sleep organization in social insects. The cost and versatility of the device and the open-source options for data analysis make this an attractive system for conducting studies on circadian rhythms in social bees under natural conditions, complementing studies on flower visits by these important pollinators. [ABSTRACT FROM AUTHOR]

Honeybee larvae and pupae form the cornerstone of colony survival, development, and reproduction. Azoxystrobin is an effective strobilurin fungicide that is applied during the flowering stage for controlling plant pathogens. The contaminated nectar and pollen resulting from its application are collected by forager bees and impact the health of honeybee larvae and pupae. The current study evaluated the survival, development, and physiological effects of azoxystrobin exposure on the larvae and pupae of Apis mellifera worker bees. The field-recommended concentrations of azoxystrobin were found to suppress the survival indices and lifespan in the larval as well as pupal stages; moreover, the rates of the survival and pupation of larvae as well as the body weights of the pupae and newly-emerged adult bees were significantly reduced upon long-term exposure to azoxystrobin. In addition, azoxystrobin ingestion induced changes in the expression of genes critical for the development, immunity, and nutrient metabolism of larvae and pupae, although the expression profile of these genes differed between the larval and pupal stages. Results indicated the chronic toxicity of azoxystrobin on the growth and development of honeybee larvae and pupae, which would affect their sensitivity to pathogens and other external stresses during the development stage and the study will provide vital information regarding the pollination safety and rational use of pesticides. [ABSTRACT FROM AUTHOR]

The comprehensive characterization of floral honeys enables a deeper understanding of their chemical composition and biological potential, which improves the market value of these honeys. This study evaluated in ten Brazilian commercial floral honeys the physicochemical characteristics (moisture, water activity, free acidity, pH, glucose, fructose, and sucrose, 5-(hydroxymethyl) furfural, diastase activity, color intensity, and electrical conductivity), aliphatic organic acids, mineral elements, phenolic compounds, antioxidant activity, and visible spectrophotometric profile. All the honey had differences (p < 0.05) in the physicochemical parameters, but were under international legislation. Gluconic acid was the major organic acid (134.62 ± 0.99–2254.35 ± 126.77 mg 100 g−1), K was the major mineral (184.92 ± 13.71–2271.23 ± 1.63 mg kg−1), and abscisic acid was the major phenolic compound (4.12 ± 3.12 µg g−1–79.62 ± 12.68 µg g−1). Eucalyptus honey presented the highest antioxidant activity, followed by multifloral and Escallonia spp. (canudo-de-pito) honey. Eucalyptus and canudo-de-pito honeys were distant from the other honey samples in the principal components analysis scatterplot (65.21% of the variability of the data explained). These findings contribute to the knowledge of the composition and quality of the floral honeys evaluated. [ABSTRACT FROM AUTHOR]

Varroa mite, Varroa destructor Anderson and Trueman (Acari: Varroidae), causes severe damage to honeybee colonies and facilitates the transmission of several bee viruses, such as deformed wing virus (DWV), which causes wing deformity in newly molted bees. In Japan, western honeybees Apis mellifera Linnaeus (Hymenoptera: Apidae) are reared for both honey production and pollination and are infested with Varroa mites. Detailed surveillance of bee viruses in both A. melliferra and V. destructor has not been conducted in Japan. We surveyed eight major bee viruses in A. mellifera and Varroa mites from Japanese apiaries. DWV is the predominant virus in both A. mellifera and V. destructor in Japan. Two strains of the virus, DWV-A and DWV-B, are considered virulent in honeybees, but only DWV-A was detected in this study. The DWV levels in honeybees were strongly correlated with the Varroa infestation rate. We also detected other viruses in both the bees and mites, such as black queen cell and Lake Sinai viruses, but at much lower infection rates than DWV. Infection rates of these viruses were higher in colonies that did not contain Varroa mites than in Varroa-infested bee colonies. Therefore, Varroa mites in Japanese apiaries could be associated with DWV transmission, but they may rarely be associated with the transmission of other viruses. [ABSTRACT FROM AUTHOR]

Honey bees are often exposed to a variety of contaminants, including pesticides from agricultural use. The aim of this study was to investigate the temporal entry of pesticides into the hive by examining the seasonal timing of honey bees bringing pesticide-contaminated pollen into their colonies and the subsequent accumulation of these pesticides in beeswax. Pollen and beeswax samples were collected biweekly from five colonies situated in an agricultural environment in Switzerland. In pollen, 23 pesticides (out of 50) were quantified, including 4 insecticides, 4 herbicides, 12 fungicides, a transformation product, an acaricide, and a synergist. The maximal insecticide concentration levels measured in individual pollen samples were 69.4 μg/kg (thiacloprid), 48.3 μg/kg (acetamiprid), 13.8 μg/kg (spinosad), and 11.1 μg/kg (indoxacarb), while fungicide levels ranged up to 2212.7 μg/kg (cyprodinil), and herbicides were up to 71.9 μg/kg (prosulfocarb). Eighteen of the pesticides found in pollen were also quantifiable in beeswax. Among these were 17 lipophilic pesticides with logarithmic octanol water coefficients (log Kow) equal or above 2.5, which showed similar temporal profiles and order of accumulation magnitude as in pollen. For example, maximal concentrations measured in individual beeswax samples were 12.4 μg/kg for indoxacarb (insecticide), 986.4 μg/kg for cyprodinil (fungicide), and 21.6 μg/kg for prosulfocarb (herbicide). Furthermore, pesticides with log Kow between 2.5 and 7.0 remained in the beeswax during wax purification. Our study shows that a large variety of pesticides brought into the hive through pollen potentially stay in the beeswax during recycling, thus constantly exposing honey bees to pesticides. [ABSTRACT FROM AUTHOR]

BACKGROUND: Bees (Apis mellifera), as important pollinators of agricultural crops, are at risk when pesticides are used. Sulfoxaflor is a new insecticide which acts on the nicotinic acetylcholine receptor (nAChR) in a similar way to neonicotinoids. The goal of this study is to evaluate the toxicity of sulfoxaflor and its effect on the A. mellifera exposure. RESULTS: Initially, developmental indicators such as larval survival, pupation, and eclosion were inhibited by 5.0 mg/L (field concentration) sulfoxaflor. In the pupal stage, fat content was significantly increased, while the glycogen content decreased. In addition, A. mellifera heads were treated with 2.0 mg/L (sublethal concentration) of sulfoxaflor and analyzed by RNA sequencing. The transcriptome results indicated that 2.0 mg/L amounts of sulfoxaflor have adverse effects on the immune, digestive, and nervous systems. Sulfoxaflor down‐regulated the expression of many genes involved in immunity, detoxification, the myosin cytoskeleton, sensory neurons, and odor‐binding proteins. CONCLUSION: Field concentration and sublethal concentration were used for the combined analysis of honeybees. The effect of sublethal concentration of sulfoxaflor on honeybees was studied for the first time from the perspective of transcriptome sequencing of honeybee head. A preliminary study was carried out on the stress of sulfoxaflor at sublethal concentration on honeybee workers, which has certain research significance and can provide theoretical basis for the use of sulfoxaflor in the field environment. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

A survey conducted as part of the National Honey Bee Survey from 2013 to 2020 quantified the managed honey bee hives on Guam, sampled accessible wild-living colonies, and described associated diseases and pests. During this period the number of managed bee colonies increased from 20 to 121 which was associated with the formation of the Guam Beekeepers Association. Managed Apis mellifera colonies on Guam had significantly fewer parasites and diseases than reported in the USA. The Varroa mite, Varroa destructor, was detected in 2014 in a wild-living colony in southern Guam. The greater banded hornet, Vespa tropica, was first observed on Guam in 2016, with honey bee depredations observed in 2017. Nosema ceranae was initially detected in wild-living and managed colonies in 2013 and has been consistently observed since that time with little apparent effect on colony health as there have been no recorded colony losses in apiaries. No small hive beetle, Aethina tumida, Tropilaelaps mite, Tropilaelaps spp, American foulbrood, Paenibacillus larvae, European foulbrood, Melissococcus plutonius, chalkbrood, Ascosphaera sp. and 11 additional viral diseases of the 22 known to infest honey bees, including deformed wing virus, were observed. [ABSTRACT FROM AUTHOR]

The invasion of the ectoparasitic mite Varroa destructor into European honey bee, Apis mellifera, populations has contributed to the collapse of most wild populations and economic losses in beekeeping operations. Understanding how some A. mellifera populations survive infestation by this parasite is of great fundamental and practical interest and has led to numerous studies of potential resistance mechanisms. One such mechanism is the uncapping and recapping of comb cells containing infested brood by nurse bees. Recapping has been observed in most surviving populations, but its link to V. destructor resistance remains unclear. Investigating the occurrence of recapping in the Eastern honey bee, Apis cerana, the original host of the parasite, could provide a better understanding of the evolution and function of this behaviour in the Apis genus. Here, we determined the frequency of recapping in two A. cerana populations in China and Thailand at different stages of brood development and compared them with a sympatric A. mellifera population in China. The species, which differ in their susceptibility to infestation, did not show significant differences in recapping frequency. A specific association between recapping and resistance to Varroa spp. in A. cerana is therefore not supported. We discuss possible functions and evolutionary scenarios for this behavior. [ABSTRACT FROM AUTHOR]

This study aimed to develop a laboratory method that allows the in vitro maintenance of honey bee drones for several days while preserving their reproductive capacity and to create a new open-source software for the automatic analysis of their sperm quality. Three experiments were performed. The first experiment was designed to validate the new open-source software named CASABee for sperm quality assessment specifically designed for the honey bee. The software was able to identify motile and static spermatozoa with high precision. Results showed a high correlation between the results of sperm quality obtained both manually and by the CASABee system (0.95 and 0.96 for sperm motility and concentration, respectively, p < 0.001). In the second and third experiments, the effect of in vitro maintenance of drones without attendant workers for four days on their ejaculatory capacity and sperm quality, respectively, was evaluated. Survival rate was 98.68%, 89.48%, 75.93%, and 60.97% on average on days 1, 2, 3, and 4 after capturing, respectively. A high proportion of the drones (80.37% on average) were able to ejaculate providing semen, and there were no significant differences in the ejaculatory capacity and sperm quality of drones on the different days of in vitro maintenance, except for sperm viability, which decreased slightly on day 4 (71.71% vs 82.8% on day 0, p < 0.05). It was concluded that the new CASABee system and the method for laboratory maintenance of honey bee drones facilitate the study of reproduction in this species. [ABSTRACT FROM AUTHOR]

The administration of beneficial microbes or probiotics is a widely used strategy to improve human and animal health. In a previous study, we developed a mixture of Apilactobacillus kunkeei strains that, when administered to honey bees, reduced the infection by pathogens Nosema ceranae or the mortality associated with Paenibacillus larvae. However, as results obtained by probiotic treatments are variable, it is necessary to monitor its adequate administration. Here, we designed specific primers to detect and quantify A. kunkeei within honey bee guts which can be a helpful strategy to monitor its administration and persistence at the field level in future studies. [ABSTRACT FROM AUTHOR]

Societal Impact Statement Summary Humans and honey bees have a long history of interaction to yield valued products and services. However, honey bees are under pressure from changes in vegetation, agricultural practices and climate change. We investigate if pasture legumes can be harnessed to support honey bees. We use a diverse set of species that originated from the Mediterranean and western Europe but are now developed as commercial cultivars for the southern Australian livestock industries. We find that pasture legumes show great promise as a means to support honey bees and suggest that further targeted research is warranted. Globally, humans and honey bees (Apis mellifera) have a long history of interaction and this is now under pressure. In temperate southern Australia, exotic honey bees rely on an unstable native floral resource base, yet a diverse set of exotic pasture legume species are sown as staple rotational or permanent crops. We investigated if these pasture legumes could be strategically used to support honey bee populations for the apiary and horticulture industries in this region. A literature review on temperate pasture legumes and honey bees was undertaken and integrated with data from an Australian industry case study. Comparisons were made to the widely‐grown red clover (Trifolium pratense) and white clover (T. repens). We found that many southern Australian pasture legumes could provide significant floral resources as well as enhanced temporal and spatial stability for honey bees due to phenological variability and broad adaptation. Honey bees will likely recognise and be attracted to their flowers and other characteristics are comparable, or potentially superior, to red and white clover, such as floret number per inflorescence, floret length, nectar volume and sucrose‐dominance and pollen protein. The floral resource diversity from pasture legume mixes could aid honey bee health and support pollinator services for adjacent crops. We conclude that the exotic pasture legumes of temperate Australia show promise for development as a sown floral resource for honey bees. Globally, further investigation is merited to maximise benefits from the integration of a diverse range of pasture legumes into agricultural landscapes. [ABSTRACT FROM AUTHOR]

In this work, we reported the synthesis of honey bee (Apis mellifera) venom-derived nanoparticles via a hydrothermal method. This method not only ensures the preservation of the bee venom's bioactive components but also enhances their potential stability, thus broadening the scope for their applications in the biomedicinal field. The synthesis method started with the homogenization suspension of bee venom, followed by its hydrothermal process to synthesize bee venom nanoparticles (BVNPs). The successful synthesis of BVNPs was characterized using various characteristic techniques such as Ultraviolet–visible (UV–Vis) spectroscopy, Fourier Transforms Infrared (FTIR) Spectroscopy, Zeta Potential (ZP), Liquid Chromatography-Mass Spectrometry (LCMS), and Transmission Electron Microscopy (TEM). The synthesis of BVNPs through biosynthesis is shown by the visible violet-brown color development at 347 nm by UV–Vis spectroscopy. FTIR analysis revealed the presence of several functional groups in the BVNPs, including alcohols (–OH), phenols (C6H5–), carboxylic acids (–COOH), amines (–NH2, –NH–), aldehydes (–CHO), ketones (–CO–), nitriles (–CN), amides (–CO–N–), imines (–CNH–), esters (–COO–), and polysaccharides. These functional groups, as confirmed by their specific stretching and bending vibrational modes, contribute to the diverse biological activities of BVNPs, including cytotoxicity against MCF-7 breast cancer cells. The ZP of the BVNPs indicated good colloidal stability at − 45 mV. LCMS analysis confirmed the presence of major bioactive molecules, including melittin & apamin and TEM analysis shows the BVNPs exhibited a quasi-spherical shape with good dispersion, the average size was approximately 25 nm, with some being smaller (quantum dots) and interplanar spacing of 0.236 nm indicated a highly ordered crystalline structure. Moreover, the anticancer efficacy of the BVNPs was ascertained through in vitro assays against MCF-7 breast cancer cells, showing a dose-dependent cytotoxic effect. The findings of this study underscore the viability of hydrothermal synthesis in producing biologically active and structurally stable BVNPs, with a significant potential for anticancer activities. [ABSTRACT FROM AUTHOR]

The miRNA plays a key role in the regulation of hormone signaling in insects. The pathways by which miRNAs affect hormone levels are unclear in the honeybee (Apis mellifera), an indispensable pollinator in nature. In this study, ame-miR-5119 was overexpressed and knocked down in larvae by feeding mimics and inhibitors, respectively, and we determined that ame-miR-5119 regulates hormone signaling through the target gene ecdysis triggering hormone (Eth), which affects the larval-pupal transition of workers. The results showed that amemiR-5119 with a length of 19 nt targets six genes related to the hormone pathway. We focused on Eth and found that ame-miR-5119 and Eth exhibited reverse expression patterns during the transition from larval to pupal stages in workers. Dual luciferase assay confirmed the negative regulatory between ame-miR-5119 and Eth. Overexpression of ame-miR-5119 decreased the mRNA level of Eth, and the Eth receptor (Ethr) expression was not significantly affected, but the expression levels of juvenile hormone (JH) pathway related genes juvenile hormone acid methyltransferase (Jhamt) and Krüppel homolog 1 (Kr-h1) were significantly reduced. In contrast, knockdown of ame-miR-5119 increased the mRNA level of Eth, and the expression of Ethr, Jhamt and Kr-h1 was significantly upregulated. ame-miR-5119 did not affect larval body weight. The number of larvae overexpressing ame-miR-5119 survived in the prepupal stage was lower than that in the control group, and the number of pupations reduced at 11-dayold. The number of larvae that knocked down ame-miR-5119 survived in the prepupal stage was significantly higher than that in the control group, and the number of pupations increased at 11-day-old. These results indicated that amemiR-5119 negatively regulates the expression of Eth, indirectly inhibits the expression of Ethr, Jhamt, and Kr-h1, and affects the JH biosynthesis, thereby preventing the metamorphic transition from larva to pupa in worker bees. These findings provide evidence that the miRNA regulation of hormone levels in honey bees. [ABSTRACT FROM AUTHOR]

The population density of the domesticated bee, Apis mellifera is affected on a large scale by pesticide application and climate changes. Furthermore, contamination of bee flora with insecticide residue is another cause of honeybee mortality. The current study assessed the toxicity of five insecticides, namely bifenthrin (Talstar®10EC), endosulfan (Thiodon®35EC), imidacloprid (Confidor®200SL), ethofenprox (Trebon®30EC) and diafenthiuron (Polo®500SC) against haemocytes of the honeybee, A. mellifera under standard laboratory conditions. Analysis for counts of total haemocytes, differential haemocytes, and abnormalities was determined for larvae, pupae, and adult worker bees of A. mellifera. The haemolymph samples were assessed soon after, 30 and 60 min for selected insecticides applied at a concentration of recommended field doses. The total count of haemocytes was found to be significantly maximum in larval and pupal stages (35818 cells/mm3, 3387 cells/mm3) while lowest (5493 cells/mm3) in adult workers, but differential counts of haemocytes remained somewhat insignificant for all insecticides applied. Variation of total haemocytes count of honeybee resulted for all tested insecticides. Results revealed an increase in haemocytes count (6662 cells/mm3, 7237 cells/mm3, 7081 cells/mm3) of adult honeybees exposed to diafenthiuron, ethofenprox, and imidacloprid soon after application; however, these counts dropped (4506 cells/mm3, 4262 cells/mm3, 3481 cells/mm3, 4325 cells/mm3) after sixty minutes of application for all tested insecticides except for bifenthrin when compared with the untreated adult honeybee. While for differential count, granulocytes and plasmatocyte numbers increased in adult worker A. mellifera after the application of insecticides. Haemocytes immune response to insecticides exhibited abnormalities of various degrees, such as denucleation, cell shape distortion and agglutination. The findings indicate that insecticides influence the immunity of A. mellifera by altering of total and differential count of haemocytes, possibly leading to increased mortality and loss of the colony. [ABSTRACT FROM AUTHOR]

Simple Summary: Among the pests infesting the honeybee Apis mellifera, the parasitoid flies Megaselia scalaris and Senotainia tricuspis are not yet well characterized for the occurrence and harmfulness to bee colonies. These flies can attack the forager bee and lay eggs or larvae on its body, which will develop by feeding on the host tissues until it is killed. Their prevalence in different countries is still not well defined, so, in this study, rapid molecular methods were developed to facilitate their detection. The new methods were applied in a preliminary analysis of adult bees and hive debris from parts of Central Italy and the Republic of Kosovo. Both flies were detected in the two countries and more frequently in Italy. The M. scalaris flies isolated from Italian apiaries were genotypically related to biotypes from distant countries. Single flies were shown to possibly transmit honeybee microbial pathogens, so their presence should be efficiently contrasted in apiaries. The Megaselia scalaris and Senotainia tricuspis parasitoid flies of the honeybee Apis mellifera were found to infest apiaries of different European and Mediterranean countries but their prevalence and impact on apiary health are little known. Therefore, in this study, quantitative PCR (qPCR)-based methods were developed for their rapid detection directly in hive matrices. The newly developed qPCR assays were targeted at the mitochondrial cytochrome oxidase subunit I (COI) gene for the M. scalaris and the cytochrome B (cytB) gene for the S. tricuspis. The tests were preliminarily applied to 64 samples of adult honeybees and hive debris collected in the Abruzzo and Molise regions, Central Italy, and the Republic of Kosovo showing that both flies occur in the two countries and more frequently in Italy. The positive apiaries in Italy were re-sampled by capturing viable forager bees and isolating emerging flies to carry out the genotyping and analyses aimed at defining if these flies can transmit honeybee pathogens. Genotyping based on the COI and cytB gene sequencing for M. scalaris and S. tricuspis, respectively, identified one S. tricuspis genotype and diverse genotypes of M. scalaris highly similar to those from distant countries. Some fly isolates harbored the DNA or RNA of honeybee microbial pathogens Paenibacillus larvae, deformed wing viruses A and B (DWVA and B), black queen cell virus (BQCV), chronic paralysis virus (CBPV), and Nosema ceranae. The results indicated that these parasites should be efficiently controlled in apiaries by using rapid detection methods to facilitate the large screening studies and early detection. [ABSTRACT FROM AUTHOR]

Stingers, evolved from ovipositors, are an important defense organ for the Apidae, Vespidae, and Formicidae species. However, the molecular mechanism of stinger development remains unclear. Here, we show that the earliest time point for the appearance of stingers in Apis mellifera is at the 1-day-old worker pupal stage based on morphological observations and anatomy from the pre-pupal to adult stages. To discover the genes related to stinger development, we first comprehensively compared the stinger transcriptome at different stages and screened 1282, 186, and 166 highly expressed genes in the stingers of 1- and 5-day-old worker pupae and newly emerged worker bees (NEBs), respectively, then identified 25 DEGs involved in the early stage of stinger development. We found that Dll was a key candidate gene in the early development of A. mellifera stingers by combining analyses of the protein–protein interaction network and spatiotemporal expression patterns. An RNAi experiment showed that about 20% of individuals exhibited tip bending in the piercing parts of their stingers in the Dll-dsRNA-treated group, with the morphology presenting as side–side or front–back tip bending. This indicates that Dll plays a vital role in the early development of A. mellifera stingers. Together, our study provides insight into the molecular mechanism of Hymenoptera stinger development and an inspiration for the molecular breeding of gentle honeybee species with stinger abnormalities. [ABSTRACT FROM AUTHOR]

ABSTRACT Peach (Prunus persica [L.] Batsch) is an important speciality fruit crop in the United States. Peach is self‐compatible, but bee pollination enhances fruit sets and diverse populations improve pollination efficiency. However, the bee diversity and abundance in peach orchards in South Carolina are unknown. To understand this, we sampled bees during peach tree bloom at two locations in South Carolina—the Clemson University Musser Fruit Research Center (MFRC) and a peach farm in Ridge Spring, South Carolina. Overall, a total of 651 bees were collected from peach orchards, of which Bombus (37%) and Apis (32%) were the most dominant genera, followed by Eucera (14%), Andrena (8%) and Habropoda (5%). Diversity indices indicate higher species richness and diversity at the Ridge Spring farm than at MFRC. Dominant species at the MFRC were Apis mellifera (36.77%), Bombus bimaculatus (29.1%), B. griseocolis (12%) and Eucera hamata (8%). In contrast, the Ridge Spring farm was dominated by A. mellifera (24.17%), Habropoda laboriosa (12%), Andrena barbara (12%), E. atriventris (11.72%) and B. bimaculatus (11.35%). In comparing the effectiveness of sampling methods, blue vane traps (BVTs) captured more bees than aerial sweep netting. Furthermore, BVTs predominantly captured larger‐sized bees, while smaller‐sized bees were more frequently collected using sweep netting. Throughout peach bloom, differences in bee abundance were observed over time as well. Our study sheds light on the bee diversity and abundance in South Carolina peach orchards, revealing variations between locations. This knowledge of bee diversity and abundance will provide baseline information on bee communities in peach orchards and will help develop suitable pollinator conservation programs. [ABSTRACT FROM AUTHOR]

The honey bee ectoparasite Varroa destructor is the main cause of honey bee colony losses worldwide. Over the last decades, several projects have focused on improving the robustness of Apis mellifera against this parasitic mite. Selection traits, such as mite non-reproduction (MNR) and Varroa sensitive hygiene (VSH), are favored selection factors in Varroa resistance projects. VSH is a trait where adult honey bees remove the Varroa-infested brood. During this process, the female mites are arrested in their reproductive cycle leading to a reduction of the Varroa population within the bee colony. From 2019 to 2022, 1402 queens were instrumentally inseminated with single or multiple drones in a breeding program. Colonies headed by these queens were established annually, and the MNR and VSH levels were analyzed. VSH was evaluated in response to cells artificially infested with Varroa, and colonies with high VSH values were used to generate our selected VSH stock. Despite crossing high VSH drones and queens, we measured a remarkable heterogeneity of MNR and VSH in the next generation(s), most likely due to the well-described, high recombination rate in the honey bee genome. When assessed multiple times in the same colony, great variance between measurements was observed. Detailed evaluations of daughter colonies are thus required if selection programs want to breed colonies with reliable VSH traits. This constant need to evaluate all offspring to ensure the desirable resistance traits are present results in high workloads and great expenses in selection programs. Furthermore, such large-scale breeding programs are inefficient due to high fluctuations between measurements and generations, indicating we need to develop new approaches and improved methods for assessing Varroa resistance. [ABSTRACT FROM AUTHOR]

Imidacloprid and other neonicotinoid insecticides severely impact the performance and survival of honey bees and other pollinators. In the present study, we focused on the gene expression profile of newly emerged Apis mellifera queen bees after sublethal imidacloprid treatment during the larval stage. Royal jelly containing 1 ppb imidacloprid was provided to larvae for 3 consecutive days (2–4 days postemergence). Queen larvae treated with imidacloprid showed lower capping and emergence rates (35.5% and 24.22%, respectively) than did control larvae (61.68% and 52.95%, respectively), indicating a high failure rate of queen rearing associated with imidacloprid exposure during the larval stage. The molecular response to imidacloprid treatment was examined next. By comparing the gene expression profiles of imidacloprid‐treated queen larvae and those of control queen larvae using DESeq2, we identified 215 differentially expressed genes, with 105 and 111 up‐ and downregulated genes, respectively. Gene Ontology results indicated that chitin binding– and calcium ion binding–related genes were upregulated, while phototransduction‐ and visual perception–related genes were downregulated. The high mortality rate and altered gene expression profiles suggest that treatment with even 1 ppb imidacloprid can severely impact queen bee survival. Environ Toxicol Chem 2024;43:2232–2242. © 2024 SETAC [ABSTRACT FROM AUTHOR]

Honey bees play a pivotal role in shaping ecosystems and sustaining human health as both pollinators and producers of health‐promoting products. However, honey bee colony mortality is on the rise globally, driven by various factors, including parasites, pesticides, habitat loss, poor nutrition, and climate change. This has far‐reaching consequences for the environment, economy, and human welfare. While efforts to address these issues are underway, the current progress in electron paramagnetic resonance (EPR) instrumentation affords using the immense potential of this magnetic resonance technique to study small samples such as honey bees. This paper presents the pioneering 2D in vivo EPR imaging experiment on a honey bee, revealing the ongoing redox‐status of bees' intestines. This way, by monitoring the spatio‐temporal changes of the redox‐active spin‐probes' EPR signal, it is possible to gain access to valuable information on the course of ongoing bees' pathologies and the prospect of following‐up on the efficiency of applied therapies. Employing a selection of diverse spin‐probes could further reveal pH levels and oxygen concentrations in bee tissues, allowing a noninvasive assessment of bee physiology. This approach offers promising strategies for safeguarding pollinators and understanding their biology, fostering their well‐being and ecological harmony. Research Highlights: Honey bees face rising mortality from parasites, pesticides, and climate change. This paper introduces original use of in vivo electron paramagnetic resonance imaging (EPRI) method to explore redox processes in honey bee intestines, advancing our understanding of these vital insects' health. [ABSTRACT FROM AUTHOR]

Kiwifruit (Actinidia chinensis var. deliciosa) has become an important horticultural crop worldwide. Its dioecious nature challenges its commercial production, involving strategies for enhancing cross-pollination to reach a better fruit quality. The explanatory variables that can be linked to improving fruit quality analyzed in this work were pollination (through a hand-pollen application or by Apis mellifera, but also considering the ratio of female:male plants in each plot) and plant competition for resources during fruit development (controlled by thinning, but also considering plant density per plot). The response variables assessed to estimate fruit quality were fruit weight, number of seeds, and shape coefficient. We obtained different models showing how these explanatory variables influence the different indicators for fruit quality (sampling 25 fruits per plot) in seven plots. Results suggest that the female:male ratio and number of plants per hectare are the most influential explanatory variables related to fruit quality in the studied agroecosystem. The kiwifruits from plots with higher amounts of pollen manually added and higher ratios of female:male plants were significantly lighter. We recommend not settling more than 500 plants per hectare at the plot level. The natural pollination for kiwifruit production can be improved if the ratio of female:male plants per plot is ≤ 10/1 when the flowering period of both plant sexes is synchronized. Finally, we recommend that growers follow these numbers in considering the importance of planting male and female plants in close proximity but managing plant density to avoid competition for resources. [ABSTRACT FROM AUTHOR]

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BACKGROUND: The parasitic mite, Varroa destructor has posed a threat to the health and survival of European honey bees, Apis mellifera worldwide. There is a prevailing belief that small comb cells could provide a management tool against Varroa mites. However, the hypothesis that smaller cells can impede Varroa reproduction has not been fully tested. Here, we tested this hypothesis under laboratory conditions by using two distinct Varroa in vitro rearing systems: one involved gelatin capsules of different sizes, specifically size 00 (0.95 mL) versus size 1 (0.48 mL), and the second consisted of brood comb cells drawn on 3D printed foundations with varying cell sizes, ranging from 5.0 mm to 7.0 mm at 0.5 mm intervals. RESULTS: The results showed that mother mites in size 00 cells had significantly lower fecundity and fertility compared to those in size 1 cells. Interestingly, the reproductive suppression in larger cells could be reversed by adding an extra worker larva. Similarly, gonopore size of mother mites was smaller in size 00 cells, but restored with another host larva. Furthermore, both the fecundity and fertility of mother mites decreased linearly with the size of brood comb cells. CONCLUSIONS: Our results suggest that the reproduction of V. destructor is hindered by larger cells, possibly because larger brood cells disperse or weaken host volatile chemical cues that are crucial for Varroa reproduction. The insights derived from this study are expected to hold significant implications for the implementation of Varroa management programs. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Simple Summary: The mite Varroa destructor is the most damaging parasite of honey bees (Apis mellifera) worldwide. When necessary, mite control is mainly accomplished with acaricides. Optimal parasite control is achieved when the acaricide is applied during times of little or no brood in honey bee colonies, which varies by region. Therefore, in this study we analyzed the population dynamics of the mite in honey bee colonies established in a temperate semi-arid climate in Mexico by periodically sampling brood and adult bees, as well as by counting mites falling to the bottom board of hives over 10 months. We also measured brood and adult bee populations and food stores. It was found that the sampling period influences the population of V. destructor in the colonies. The mite population increased by 26% in the 10 months of sampling. It was observed that as the worker brood population increased, the mite infestation rate in adult bees decreased, and the opposite occurred when the amount of brood in the colonies was reduced. Monitoring V. destructor populations by recording fallen mites is more reliable than determining mite infestation rates in adult bees and brood. The best period to apply an acaricide treatment in the region of study is between November and December. This study aimed to analyze the population dynamics of the mite Varroa destructor in honey bee (Apis mellifera) colonies in a temperate semi-arid climate in Mexico. Ten colonies homogeneous in population, food stores, and levels of mite infestation were used. The mite infestation rate in brood and adult bees, total number of mites, daily mite fall, brood and adult bee population, and food stores were determined periodically for 10 months. There was a significant effect (p < 0.05) of sampling period on the population of V. destructor in adult bees, brood, total mite population, and daily fallen mites. The total mite population increased by 26% on average per colony. The increase in brood amount reduced the mite infestation rate in adult bees, and the opposite occurred when the brood decreased. Monitoring V. destructor populations by recording fallen mites is more reliable than determining mite infestation rates in bees, as mite fall has a dynamic pattern similar to that of the total mite population. The best period to apply an acaricide treatment in the region of study is between November and December because most mites were in the phoretic phase, since there was less brood in the colonies compared to other times. [ABSTRACT FROM AUTHOR]

Simple Summary: Varroa destructor is a significant global honey bee parasite and the primary threat to bee health. Due to its latent lifestyle, detecting the mite in a brood requires invasive techniques. Enhancing detection methods is critical for advanced research on mite population dynamics, spread, selection efforts, and control methodologies. In this study, we employed infrared thermal imaging, a less-explored technique in apicultural studies, to detect parasitism in Apis mellifera broods. Our findings indicate that handheld infrared thermal cameras can generate adequately detailed heat maps of the hive. These maps distinctly separate cells containing honey, pollen, and brood, with stable, reproducible temperature measurements observable in late autumn. Notably, mite parasitism induces a sustained temperature increase in developing honey bee pupae, consistently detected regardless of mite numbers in the cell. This study reveals an advanced thermoregulatory behavior in the honey bee colony, manifesting as a social fever phenomenon. Further research is necessary to explore the health benefits of this behavior for bees and the negative effects on the mite. Our method, combined with the development of AI-based image evaluation software, could provide beekeepers and researchers with a valuable tool for Varroa research and bee biological studies. The Varroa destructor is the most significant bee parasite and the greatest threat to bee health all around the world. Due to its hidden lifestyle, detection within the brood cell is only possible through invasive techniques. Enhancing detection methods is essential for advancing research on population dynamics, spread, selection efforts, and control methodologies against the mite. In our study, we employed infrared imaging to measure the thermal differences in parasite and intact Apis mellifera worker broods. Experiments were conducted over two years at the MATE Kaposvár Campus in Hungary involving five beehives in 2022 and five beehives in 2023. A FLIR E5-XT WIFI handheld infrared camera was used to create a heat map of capped brood frames. Our results indicate that the resolution of these cameras is sufficient to provide detailed IR images of a bee colony, making them suitable to detect temperature differences in intact and Varroa parasitized capped brood cells. Mite parasitism causes a time-dependent and sustained temperature increase in developing bee pupae, observable regardless of mite number. Our work demonstrates two different heating patterns: hotspot heating and heating cells that are responsible for the elevated temperature of the Varroa-infested cells as a social fever response by the worker bees. Based on our results, future research combined with AI-based image evaluation software could offer beekeepers and researchers practical and valuable tools for high-throughput, non-invasive Varroa detection in the field. [ABSTRACT FROM AUTHOR]

Simple Summary: In the Yucatán Peninsula, the availability and diversity of plants as food sources for bees vary throughout the year, which impacts dietary composition during the larval phase and compromises the development of their reproductive organs. We evaluated the eversion of the copulatory apparatus, ejaculation, and sperm quality of drones bred during flowering-scarcity (November–December) and flowering-onset periods (January–February). It was observed that more drones had a complete eversion of the copulatory apparatus during the flowering-onset period, with better ejaculation and sperm quality than those bred during the period of flowering scarcity. Insufficient protein intake during the larval phase of drones affects the development of reproductive organs and spermatogenesis. The aim of the study was to evaluate the effect of the flowering-scarcity and flowering-onset periods on the eversion of the copulatory apparatus, ejaculation, and sperm quality of drones (Apis mellifera L.). To stimulate the laying of drone eggs during the flowering-scarcity period, 1 L of sugar syrup was supplied weekly to the hives, along with a protein supplement made of 20% pollen and 80% brewer's yeast. During the periods of flowering scarcity and the onset of flowering, 800 drones were collected (200 per month). At the onset of flowering, 270 drones showed eversion of the copulatory apparatus, of which 162 ejaculated, compared to the flowering-scarcity period, where 112 drones showed eversion of the copulatory apparatus and 39 drones ejaculated. During the period of flowering onset, sperm parameters such as volume, concentration, motility, viability, acrosome integrity, and mitochondrial activity were higher compared to the period of flowering scarcity. In conclusion, we observed a greater number of drones with eversion of the copulatory apparatus and ejaculation, as well as better sperm quality with the drones bred during the period of flowering onset. These differences indicate that the flowering-scarcity period significantly impacts the reproductive parameters of drones. [ABSTRACT FROM AUTHOR]

Honey bees are crucial to human survival in their role as generalist pollinators. However, humans also impact honey bees through the use of agricultural chemicals, typically aimed at increasing crop yield. Pesticide exposure to honey bees has been associated with a decrease in colony growth and fewer queens being born. However, the safety of pesticides is derived from acute feeding studies that focus on mortality. Pesticides are now ubiquitous in the environment and honey bees are constantly exposed. Studies utilizing long-term exposure better represent the lifetime experience of a typical honey bee. Here we measured changes in associative learning following 1 week of exposure to one of two sub-lethal, field-relevant doses of imidacloprid. While neither concentration of pesticide altered mortality relative to control, learning acquisition decreased in the high compared to control groups. These data demonstrate that chronic exposure to field-relevant doses of imidacloprid impact the ability for honey bees to form memories. The foraging success of honey bees relies on remembering the location of the hive and potential forage locations. [ABSTRACT FROM AUTHOR]

Honeybees are important insects, both economically and as pollinators. While foraging, bees can come in contact with environmental pollutants such as pesticides, possibly in combination with other xenobiotic compounds that may compromise bee health. Our current study investigated the acute exposure to nanosized titanium dioxide, a common additive in food, cosmetics, paints and agricultural products, along with deltamethrin (DLT), a well‐known pyrethroid pesticide. The effects of binary exposure to titanium dioxide nanoparticles (TiO2‐NPs) nanoparticles at concentrations of 25, 50, 75 and 100 μg/mL with DLT were noted on Apis mellifera brain histology along with their possible synergism. In DLT‐ and combined TiO2‐NP‐DLT treated bees, survival rates were lowered and several histological alterations were observed including an increased number of cells with pyknotic nuclei, along with cytoplasmic vacuolization, chromatin compaction and degeneration indicating autophagic activity and a decrease in the cross‐sectional area of nanoparticle‐treated mushroom body calyces. A synergistic relationship between TiO2‐NPs and DLT was revealed, while LD50 for combined TiO2‐NP‐DLT treatment was 0.101, 0.09 and 0.02 μg/bee at 24, 48 and 72 h, respectively. In summary, results demonstrate that TiO2‐NP and DLT co‐exposure can induce damage in bee brain structures at higher concentrations, which indicates an additional risk factor for bee health in the field. [ABSTRACT FROM AUTHOR]

Since beekeeping is directly dependent on land-use patterns, beekeeping is much more affected by land-use changes than other sectors. As land-use changes have accelerated over the past decade, beekeeping is becoming more vulnerable and the need to monitor the response of the honey bee colonies to land-use changes is more important than ever. In this study, land-use changes were identified and future projections were made to determine whether the study area will provide new opportunities for beekeeping or whether valuable land will be irretrievably destroyed. One of the main objectives of this study is to show the future trends of the Turkish apicultural sector and its response to land-use changes along with changes in agriculture, forests, urban and natural plant areas in 2025, 2040 and 2050. The results show that by 2050, a total of 2840 km2 of fruit tree, 883.2 km2 of agricultural area will increase, and 1481.4 km2 of forest area will be lost. Since the largest expansion is expected in fruit trees (citrus in the study area), land-use changes were assessed by analyzing honey statistics for citrus and the contribution of honey bees to citrus pollination to verify the reliability of the predictions. [ABSTRACT FROM AUTHOR]

Simple Summary: Economically, Varroa destructor is the most important parasite to honey bees. There are many ways to deal with it, including pharmaceutical and biotechnological treatments. However, the mite has become resistant to many synthetic pesticides. There is little research on its response to organic acids. This report examines the question of whether it could become resistant to oxalic acid. The review uses literature from the past 30 years, and calculates and reviews the annual median efficacy for different application methods. If an efficacy of 70% or more is achieved, it can be concluded that the organism is not resistant. There is no evidence of resistance development, despite some outliers, which can be explained by the studies. Further tests are required to confirm the results. As Varroa destructor is one of the most important pathogens of Apis mellifera, there are numerous treatment methods, including pharmaceutical and biotechnological approaches. However, the rapid development of resistance to synthetic acaricides by Varroa destructor has become a significant concern. To date, there have been no investigations into the development of resistance to organic acids. This review examines the potential risk of oxalic acid resistance development by evaluating literature sources from the past 30 years following the PRISMA 2020 guidelines. Median annual efficacies are calculated and reviewed over time for several application methods. An efficacy higher than 70% is determined as not resistant. Independent of the method of application, no resistance development can be observed, although there are some outliers of the annual median. These outliers can be explained by brood status or study setting. However, the result is limited by the low number of efficacy values, and further standardised studies are needed. [ABSTRACT FROM AUTHOR]

With the steady rise in antifungal resistance amongst clinically important yeasts, antifungal drug discovery remains of the utmost importance. To determine the potential of some honeys as alternative antifungal agents, we quantified the antifungal activity of 12 Western Australian honey samples, two Manuka honey samples and an artificial honey against 10 yeast isolates including clinical and reference strains. Results showed that the tested honeys varied in activity, and yeasts species also differed in susceptibility, with minimum inhibitory concentrations (MICs) determined by broth microdilution ranging from 8% to >44% w/v honey. Honeys with the highest overall activity were derived from Blackbutt (Eucalyptus patens), Jarrah (E. marginata), and Karri (E. diversicolor). The optical density of each MIC microtitre plate was determined after incubation and showed that at relatively low concentrations of honey the growth of all yeasts was enhanced compared to the untreated control, whereas at and above approximately 12% w/v, honeys exerted a dose‐dependent growth inhibitory effect, the extent of which varied by honey type. Time‐kill studies with 64% w/v honey showed that all eight of the natural honeys tested had greater fungicidal activity than the comparator artificial honey. Our findings suggest that the specific nectar‐derived phytochemicals present within each honey play an important role in antifungal activity, and support the notion that activity is due to a combination of factors including osmotic activity, hydrogen peroxide and phytochemical compounds. These data indicate that honey is worthy of further investigation as a potential therapeutic agent for superficial yeast infections. Take‐away: All honeys tested demonstrated dose dependent inhibition of tested yeasts.Honey, at high concentrations, is fungicidal for tested yeasts.A combination of osmotic, physicochemical, and phytochemicals are responsible. [ABSTRACT FROM AUTHOR]

Purpose: Nosemosis is a disease that infects both Western honeybees (Apis mellifera L.) and Asian honeybees (Apis cerana) and causes colony losses and low productivity worldwide. In order to control nosemosis, it is important to determine the distribution and prevalence of this disease agent in a particular region. For this purpose, a national study was conducted to assess the prevalence of Nosema ceranae and N. apis throughout Türkiye, to perform network analyses of the parasites, and to determine the presence of nosemosis. Methods: In this study which aimed to assess the prevalence of N. apis and N. ceranae in different colony types and regions where beekeeping is intensive in Türkiye, specimens were collected from hives with no clinical signs. Results: A total of 1194 Western honeybee colonies in 400 apiaries from 40 provinces of Türkiye were examined by microscopic and molecular techniques. Nosemosis was found in all of 40 provinces. The mean prevalence ratio was 64.3 ± 3.0, with 95% CI in apiaries and 40.5 ± 2.9, 95% CI in hives. Nosema ceranae DNA was detected in all of positive hives, while N. ceranae and N. apis co-infection was detected in only four colonies. Conclusion: This study showed that nosemosis has spread to all provinces, and it is common in every region of Türkiye. All of the N. ceranae or N. apis samples examined were 100% identical within themselves. Network analysis showed that they were within largest haplotype reported worldwide. [ABSTRACT FROM AUTHOR]

BACKGROUND: The Varroa mite (Varroa destructor) is considered to be the greatest threat to apiculture worldwide. RNA interference (RNAi) using double‐stranded RNA (dsRNA) as a gene silencing mechanism has emerged as a next‐generation strategy for mite control. RESULTS: We explored the impact of a dsRNA biopesticide, named vadescana, designed to silence the calmodulin gene in Varroa, on mite fitness in mini‐hives housed in a laboratory. Two dosages were tested: 2 g/L dsRNA and 8 g/L dsRNA. Vadescana appeared to have no effect on mite survival, however, mite fertility was substantially reduced. The majority of foundress mites exposed to vadescana failed to produce any offspring. No dose‐dependent effect of vadescana was observed, as both the low and high doses inhibited mite reproduction equally well in the mini‐hives and neither dose impacted pupal survival of the honey bee. Approximately 95% of bee pupae were alive at uncapping across all treatment groups. CONCLUSION: These findings suggest that vadescana has significant potential as an effective alternative to conventional methods for Varroa control, with broader implications for the utilization of RNAi as a next‐generation tool in the management of pest species. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Sunflower production depends on pollination by honey bees, Apis mellifera L., and wild bees. For wild sunflower oligoleges, preference for various sunflower lines seems to reflect the quantity (or accessibility) of floral rewards, with floret size (≈accessibility of sunflower nectar) appearing most important. However, it is less clear how honey bees, a key generalist, are affected by sunflower floral traits. The honey bee-sunflower interaction was explored to test if accessibility of nectar (≈floret size) and related floral traits explain foraging preferences and to assess potential nutritional variation in sunflower pollen. In the first two years, honey bee foraging preference increased with decreasing floret length similar to previous observations with wild pollinators. In the second year, no similar response was seen, though nectar rewards (by volume or volume × concentration) were remarkably low compared to the previous year. Pollen collected from bagged plants in the second year showed sunflower lines differed in concentrations (µg/mg ± SE) of total fatty acids and essential fatty acids. In general, it appears that honey bee responses to floral traits are similar to those of wild bees responsible for pollinating much of the sunflower crop in the central United States and that variation in the nutritional quality of sunflower pollen is greater than previously known. Because of the broad geographic distribution of the sunflower crop, additional research on how the environment influences floral rewards and sunflower-pollinator interactions may be needed. [ABSTRACT FROM AUTHOR]

Bee-collected pollen is stored in the colony and mixed with bee saliva and microorganisms, resulting in pollen's fermentation and acidification. Pathogens infecting the colony, including the deformed wing virus (DWV), may be transferred into the bee bread (BB). In this study, we used an in vivo infection assay to determine whether DWV remains infective in BB. We also used Lactobacillus kunkeei to ferment UV-treated fresh pollen. This fermented pollen in vitro (FPV) was used as a virus-free reference for the initial viral loads in BB and to evaluate the effect of controlled bacterial fermentation on the infectivity of DWV. Finally, we investigated the thermal inactivation of DWV in BB and FPV. To accomplish these goals, we added DWV inoculum to BB and FPV and heated them at 70 °C or 60 °C for 1 h. Suspensions of the virus recovered from the treated pollen samples were injected into pupae to evaluate the degree of viral viability and the efficacy of thermal inactivation. We found that the virus recovered from non-thermally treated BB and FPV samples remained highly infectious in the pupal injection assay. Overall, BB and FPV treated at 60 °C had an average reduction of 98.69% of viable DWV copies, while treatments at 70 °C inactivated DWV almost entirely (99.99%). This study demonstrates that DWV remains infective in BB and that thermal inactivation is an effective strategy for significantly reducing levels of viable DWV in contaminated pollen. [ABSTRACT FROM AUTHOR]

The most devastating pest to honey bees (Apis mellifera) worldwide is the parasitic mite Varroa destructor. The development of miticide-resistant mite populations has been a major driver of colony loss in many countries. We investigated the threat Varroa poses to honey bee populations in New Zealand and tested the effectiveness of the two most popular chemical treatments used by beekeepers. Colony losses reported by New Zealand beekeepers have risen over five consecutive years from 2017 to 2021, as have the proportion of losses attributed to Varroa, with this parasite found to be the main driver of colony loss in 2021. Varroa resistance to miticide treatments flumethrin and amitraz was tested. The concentration of flumethrin required to kill 50% of the mites (LC50) was 156 µg/g, 26 times greater than the adjusted LC50 value of 6 µg/g observed in a trial also conducted in New Zealand in 2003, indicating evidence of developing mite resistance to flumethrin in New Zealand. Molecular analyses searching for mutations in the Varroa genome known to be associated with flumethrin resistance found no evidence of such mutations, suggesting that any extant resistance to flumethrin has evolved independently in New Zealand. No evidence of resistance to amitraz was found, as the LC50 value of 12 µg/g was lower than what was observed in the 2003 trial (141 µg/g). Further development of integrated pest management, such as with gene-silencing RNA interference (RNAi) and selective breeding of Varroa-resistant bees, is needed to effectively manage a parasite that threatens global agriculture. [ABSTRACT FROM AUTHOR]

Here, we present a retrospective study on honey bee brood diseases in the USA. The Bee Disease Diagnostic Laboratory (BDDL) in the USDA-ARS Beltsville Bee Research Laboratory received a total of 4790 brood samples between 2015 and 2022 from U.S. State Apiary Inspectors and beekeepers. Samples from 49 states were analyzed by microscopy for the presence and prevalence of two bacteria, Melissococcus plutonius and Paenibacillus larvae, causing European foulbrood (EFB) and American foulbrood (AFB) diseases, respectively. Samples that tested positive for AFB were cultured and subjected to antibiotic susceptibility tests via the agar disc diffusion method to determine their resistance to tetracycline (Terramycin®) and tylosin (Tylan®) antibiotics. A comprehensive data analysis was conducted at multiple levels, including state, month, year, nationwide, and climate region. Among the 49 states examined, EFB was identified in 44 states, while AFB was found in 31 states. Infection levels vary across states, ranging from 0% to 63.6% for EFB and from 0% to 54.8% for AFB. The national average of EFB (19.2%) was significantly (p < 0.001) higher than AFB (8.6%). Contrary to AFB, significant yearly increases (p < 0.001) were identified for EFB from 2015 to 2022. Furthermore, significant monthly variations were recorded for both brood diseases, with the highest occurrence of EFB observed from April to July. States with the lowest infection rates of both diseases were NV, ND, MS, AK, and AZ. The South U.S. climate region, which comprises six states, had the highest and lowest EFB and ABF infections, respectively. On a nationwide scale, the AFB resistance to tetracycline (38%) was significantly (p < 0.001) higher than the resistance to tylosin (27%). [ABSTRACT FROM AUTHOR]

Honey bees can be evaluated to study their economic, developmental and immunity aspects. Apis mellifera has important organs such as the hypopharyngeal gland, mandibular gland and brain in their heads. The hypopharyngeal glands and mandibular glands cooperate to produce royal jelly essential in feeding queen honey bees and broods. Moreover, the brain is an organ that regulates the social behaviors of honey bees such as memory and learning. Therefore, this study aimed to detect differential head protein changes in one-day-old and nine-day-old worker honey bees. 153 repeatable protein spots were identified using Melanie software and statistically analyzed. Of the total protein spots, 27 responsive spots were identified using MALDI TOF-TOF mass spectrometry, of which 14 and 8 spots showed up and down regulation, respectively and five spots were expressed just in the head capsules of nine-day-old workers. All identified proteins were divided into 16 different groups involved in various growth-related processes as well as royal jelly augmentation. Nine proteins including KMT5B, TGIF2LX, Protein mono-ADP-ribosyltransferase PARP12, TCL1B4, maph-9, Vimentin-type intermediate filament-associated coiled-coil protein, HSP68, tetratricopeptide repeat domain 36 and POC1B were also identified and introduced for the first time in A. mellifera. This study provides valuable information on proteins involved in honey bee head growth and development as well as increasing royal jelly production. [ABSTRACT FROM AUTHOR]

Brazil is the major global soybean producer with ca. 40 million hectares grown annually. In recent years, there has been a growing interest by beekeepers to migrate their hives close to soybean fields, to allow honey bees, Apis mellifera L. 1758 (Hymenoptera – Apidae) to forage in. To understand the effect of honey bee pollination on the soybean yield, one experiment was set up in Londrina, Brazil, to assess the yield of soybeans and its components, whose flowers were visited by honey bees, compared to those not visited. The experiment was repeated for three consecutive years, during the 2017 to 2020 soybean growing seasons. Treatments consisted of (1) open plots, with free access by honey bees; (2) caged plots with a honey bee hive inside; and (3) caged plots with no access by honey bees or any other pollinator. Monitoring visits by honey bees to soybean flowers indicated consistent visits in open and caged plots with a beehive, and larger numbers of honey bees were observed visiting soybeans at 11 am. The average yield for the three years revealed a significant increase when honey bees had access to flowers: 5,565 kg/ha for caged plots with honey bees and 5,201 for open plots, compared to caged plots without honey bee hives, which yielded 4,926 kg/ha. The yield increase was mainly associated with the occurrence of more 3 and 4-seeded pods, a larger number of seeds/pod and seed weight, as well as a smaller number of pods with zero or one seed observed in treatments with the presence of honey bees, compared to the caged plots without beehives. [ABSTRACT FROM AUTHOR]

Mushroom extracts have been shown to contain bioactive compounds that confer health benefits to humans and animals, including honey bees. Honey bees are often challenged simultaneously with several abiotic (e.g., pesticides and poor nutrition) and biotic (e.g., parasites and pathogens) stressors. Mushroom extracts, for example, those made from Agaricus bisporus, may hold the potential to mitigate the negative effects of these stressors through actions on the honey bee's immune system, metabolism, and other physiological processes. Exploring the health benefits of mushroom extracts for honey bees requires a basic understanding of their bioactive properties at the cellular level. The aim of the present study was to evaluate, for the first time, the genotoxic and antigenotoxic potential of A. bisporus on the honey bee cell line AmE-711 using the comet assay. Three increasing concentrations of A. bisporus water extract (100, 200, and 400 µg/mL) were tested. The cells in the negative control group were not treated either with A. bisporus extract or with H2O2. In the positive control group, DNA damage was induced with 100 µM H2O2. For antigenotoxic effect, tested extracts were mixed and incubated with H2O2. None of the tested concentrations exerted genotoxic potential, but all showed antigenotoxic effects against H2O2-induced DNA damage. The concentration of 200 μg/mL A. bisporus extract was the most effective in its action against DNA damage. To conclude, A. bisporus extract did not demonstrate genotoxic effects but showed promising antigenotoxic properties. AmE-711 cell line may serve as a cell culture system for genotoxicity investigations. [ABSTRACT FROM AUTHOR]

Of twenty species of beetles across six families and fourteen genera found living within the hives of the western honey bee Apis mellifera, only the small hive beetle (SHB), Aethina tumida, displays attributes characteristic of an integrated parasitic lifestyle. This species is a pest that can cause severe damage to weakened hives. SHB adults tend to disperse over long distances after they eclose and appear to rely on food odors to locate beehives to infest. Thus, we hypothesized that the floral sources of nectars processed into honey stored in hives may influence SHB orientation toward hives and dietary preferences within hives. We carried out preference assays of individual SHB in an arena with several protein patty substitute diets, each of which was prepared with one of three monofloral honeys (white tupelo Nyssa ogeche, black locust Robinia pseudoacacia, and buckwheat Fagopyrum esculentum) or a phytochemical-free control. Male and female beetles displayed different responses to food choices. Female SHB preferred monofloral honey diets (74%) over the phytochemical-free control, and, among the three monofloral honeys, exhibited a strong preference for the white tupelo honey diet over control diets. In contrast, 41% of male SHB in individual assays preferred the control diet over diets containing monofloral honeys. These findings suggest that for males the ability to detect sugar sources is the primary determinant of preference, whereas, based presumably on nutritional requirements in support of oviposition, female SHB may be responsive to a broader range of food-related cues to increase the likelihood of identifying well-provisioned hives. [ABSTRACT FROM AUTHOR]

The mandibular glands (MGs) of honey bee workers are key exocrine glands responsible for the biosynthesis of multiple royal jelly acids, which have important functions within the colony. However, our knowledge about the nutrition requirement of MGs is quite limited. Here, we artificially manipulated the nutritional status of caged honey bee workers (pollen and sugar candy, sugar candy only, soybean meal and sugar candy, stearic acid supplemented sugar candy or citric acid supplemented sugar candy). Then we measured their impact on the 10-hydroxy-2-decanoic acid (10-HDA) and 10-hydroxydecanoic acid (10-HDAA) content in honey bee heads to evaluate the synthesis ability of workers' MGs, and analyzed the protein content of MGs as well as gene expression in the MGs to reveal the possible physiological changes. Our result showed that nutrition strongly impacted the MGs acid synthesis, the 10-HDA and 10-HDAA contents were significantly higher in workers fed with pollen than with sugar candy only, while an additional supply of protein and organic acid showed no significant contribution. In addition, the 10-HDA/10-HDAA ratio was also significantly affected by the nutrition status. On the contrary, different diets showed no influence on the protein content or gene expressions of MGs, except that organic acid supplements could increase the expression of key genes in fatty acid β-oxidation pathways. Taken together, our study revealed that honey bee nutritional status is closely related to the function of worker MGs. The nutritional deficiency has a significant negative impact on the synthesis ability of worker MGs, but showed no effect on the physiology of MGs. [ABSTRACT FROM AUTHOR]

Honey bees provide key ecosystem services i.e., pollination but are functioning under various biotic and abiotic stresses. Among various stresses, thiamethoxam has been criticized worldwide. Since no scientific study on its sub-lethal effects on honey bees has been conducted in India, the present work was carried out at the Department of Entomology, Punjab Agricultural University, Ludhiana for two seasons during 2017-19. The median lethal dietary dose (LDD50) of thiamethoxam upon chronically feeding the sub-lethal doses for 10 days for a group of adult Apis mellifera bees (age 10 days) was 0.421 ng bee−1 day−1. At this level, the reduction in the area of an acinus of the hypopharyngeal gland was significant i.e., 36.62 and 37.92 percent over control during spring and winter seasons, respectively. The adverse impact of thiamethoxam on hypopharyngeal glands will be limiting the development and productivity of the honey bee colonies. [ABSTRACT FROM AUTHOR]